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healyje
May 14, 2007, 6:56 PM
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fulton wrote: Solve in a unified way. Equalization vs. Extention Equalization vs. Redundany Redundancy vs. Extension. All three variables to be concidered EQUALLY important.
I'm guessing you didn't wade through the 'Improved Sliding X' thread. Redundancy is a static variable with regards to the requirements. Equalization vs. Extension is the primary challenge, with testing showing Extension to be a bit less of a bugaboo than it was always assumed to be.
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niloc
May 14, 2007, 7:02 PM
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healyje wrote: fulton wrote: Solve in a unified way. Equalization vs. Extention Equalization vs. Redundany Redundancy vs. Extension. All three variables to be concidered EQUALLY important. I'm guessing you didn't wade through the 'Improved Sliding X' thread. Redundancy is a static variable with regards to the requirements. Equalization vs. Extension is the primary challenge, with testing showing Extension to be a bit less of a bugaboo than it was always assumed to be.
And in particular when this extension is only a few inches as in the equalette - it has been proven to be a non-issue - see my previous post and link. Also discussed in the latest Long/Gaines book.
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asdf
May 16, 2007, 4:29 AM
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Anyone pull test anything? I've shared the arrangement presented in this thread to a few folks and everyone has been more than content with the safety of the knots.
Here are the a few ways I can see the knots failing:
1. reducing the strength of the cord due to the type of limiter knots. - wouldn't you also have this concern with the two strand equalette?
2. The double fisherman pulling through? is anyone really worried about this?
3. having the overhand roll off the end. - can't see it happening with the fisherman backed against it.
Does anyone see any other concerns here or is this it?
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binrat
May 16, 2007, 12:43 PM
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asdf wrote: Anyone pull test anything? I've shared the arrangement presented in this thread to a few folks and everyone has been more than content with the safety of the knots. Here are the a few ways I can see the knots failing: 1. reducing the strength of the cord due to the type of limiter knots. - wouldn't you also have this concern with the two strand equalette? 2. The double fisherman pulling through? is anyone really worried about this? 3. having the overhand roll off the end. - can't see it happening with the fisherman backed against it. Does anyone see any other concerns here or is this it?
I plan to rig it this weekend and have a failure in 1 anchor. Planned weight about 180-210 Kg. I plan to try it with the overhand knot, with the running ends having a dbl overhand knot, and then trying it with the figure 8 bend that includes the running end. If my camera works I'll attached the pics once done.
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knudenoggin
May 17, 2007, 6:07 PM
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the_climber wrote: This is one of the ideas I tried this weekend.
a simple and effective idea put forward a few times:
simply make your equalizing powerpoint runner with a 60cm/24" HMPE sewn sling,
and, with it being the "V" of the anchor point, tie into each bight-end of this tape "V"
with the twin 6-7mm nylon cord, using a sheet bend or variant. The cord will
thus run from the anchor placements to the "V" corners, crossing between them
and so closing the "V" into a triangular loop, such that only ONE 'biner need be
clipped--solves the clip-each-strand or the clip-into-X issues.
With a 2-foot sling, each side of the "V" is 1 foot; extension from one arm failing
is a bit complicated by some swing of the line of tension, but from just
the material gain in this arrangement, it will be a half foot, if the nylon cord contributes
1 foot in closing the "V" (so, an equilateral triangle with 1 foot sides, makes a
closed loop 3' in circumference, and on isolated-arm loading, the length of this loop
is 3/2 = 1.5', a half foot longer than if both arms are in place).
This Extension-Limiting Equalization Triangle (ELET) uses common gear,
minimal 'biners (just 1 for the attachment vs. 2 of Equalette), and is pretty
simple to set up.
In reply to: My question would be how are these knots going to behave when ring loaded? ... Does anyone know how well a double fisherman's handels ring loading?
the knot to do pretty well, in the given couple of ropes tested.
cf http://www.gudelius.de/spst.htm
*kN*
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the_climber
May 17, 2007, 7:03 PM
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knudenoggin wrote: the_climber wrote: This is one of the ideas I tried this weekend. I continue to find it surprising that all this build-a-better-anchor theorizing ignores a simple and effective idea put forward a few times: simply make your equalizing powerpoint runner with a 60cm/24" HMPE sewn sling, and, with it being the "V" of the anchor point, tie into each bight-end of this tape "V" with the twin 6-7mm nylon cord, using a sheet bend or variant. The cord will thus run from the anchor placements to the "V" corners, crossing between them and so closing the "V" into a triangular loop, such that only ONE 'biner need be clipped--solves the clip-each-strand or the clip-into-X issues. With a 2-foot sling, each side of the "V" is 1 foot; extension from one arm failing is a bit complicated by some swing of the line of tension, but from just the material gain in this arrangement, it will be a half foot, if the nylon cord contributes 1 foot in closing the "V" (so, an equilateral triangle with 1 foot sides, makes a closed loop 3' in circumference, and on isolated-arm loading, the length of this loop is 3/2 = 1.5', a half foot longer than if both arms are in place). This Extension-Limiting Equalization Triangle (ELET) uses common gear, minimal 'biners (just 1 for the attachment vs. 2 of Equalette), and is pretty simple to set up.
OK, so I just went cross-eyed reading that....
knudenoggin wrote: In reply to: My question would be how are these knots going to behave when ring loaded? ... Does anyone know how well a double fisherman's handels ring loading? Testing done by Edelrid for Jost Gudelius for an Offset Grapevine Bend showed the knot to do pretty well, in the given couple of ropes tested. cf http://www.gudelius.de/spst.htm *kN*
Thanks
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knudenoggin
May 18, 2007, 6:34 AM
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Perhaps the following schema (ah, the good ol' days of ASCII Art!)
will clarify my words which crossed your eyes. The HMPE (Spectra/Dyneema)
sling is chosen for slickness, enhancing the sliding of the (lone) 'biner;
the twin nylon cord is chosen for some elasticity and knottability.
P P
.. .. <---cord hitched/clipped to protection
.. ..
.. ..
.. .. } 6-7mm twin nylon cord
.. ..
.\\:::::::::://. <--tied to bight ends of sling w/sheet bends (or ...)
\\ // (the cord between sling ends might be slacker)
\\ //
\\ // } 6-12mm HMPE sling "V" (hence, dbl. strands)
\\ //
\\//
B } one locker at the powerpoint (or more ...)
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the_climber
May 18, 2007, 4:12 PM
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Ah, Gotcha!
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asdf
May 19, 2007, 4:39 AM
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Looking at that study on the strength of the double fisherman's, am I reading it correctly when it says that it does not roll and it holds between 21 and 28 kN when the knot is ring loaded?
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knudenoggin
May 19, 2007, 8:43 PM
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Yes, the daN shifts the radix point left to KN, and those are the figures
reported for the Offset Grapevine Bend.
It's worth noting that many offset bends can be oriented in a range of
positions--lightly tension the rope and rotate the knot body, i.e.--,
so one can't take these isolated tests, and tests that didn't recognize
this variability, as definitive.
But I think it's a fair indication of the knot's security & strength
adequate for the use in question.
*kN*
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binrat
May 23, 2007, 2:44 PM
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Well,
I did three tests with a 183 kg load ( 180 kg of bagged concrete and 3 kg for the skid) In each test 1 anchor failed by means of having a link made of para cord which was cut after loading. This was a static failure. The knot tested was the overhand knot with a back-up knot on the running end of the cord. It was tested with Mammut 7 mm static cord. Of the three possible strands that could have been clipped, only 1 was clipped for 2 of the tests. The 3rd test 2 strands was clipped.
What happened:
1. On the single strand tests the knot rolled until it was tight against the back-up knot. Distance prior test between knots was 38 1/2", after on two strands was 39 1/4, and on the loaded strand 42 3/4.
2. On the double strand test, the know again rolled marignally. Lengthening of the 2 strands was marginal.
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elnero
May 25, 2007, 6:14 AM
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trenchdigger wrote: I'm also curious how others attach an auto-blocking belay device to a redundant part of an equalette anchor. I don't see how it can be done without twisting the equalette into a sliding X (degraded equalization) or using a device that accepts two carabiners (Trango B52 + 2 lockers in an equalette at a hanging belay = cluster F#@%). My idea makes all this much easier while maintaining the benefits of an equalette.
Theres been a few threads about creating a master point of sorts with the equalette for belaying with an autoblock. The method that seems best for me is to tie a bunnyeared figure 8 from your harness and clip that into the two lockers, then clip your atc into the two loops on the figure 8 knot.
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asdf
Aug 18, 2007, 5:27 AM
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Out of curiosity, has anyone adopted the use of the "three strand" equalette since this thread developed?
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landongw
Aug 18, 2007, 6:11 AM
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this is the most ridiculous troll i've ever seen. i can't believe so many people are dumb enough to take it seriously.
if this isn't a troll, then you're a complete moron.
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asdf
Aug 19, 2007, 3:13 AM
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Asshole meter:
Assholes: 1
Responses: 0
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ja1484
Apr 11, 2008, 3:46 AM
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asdf wrote: Out of curiosity, has anyone adopted the use of the "three strand" equalette since this thread developed?
Thread revive.
Yes, actually. My partner and I have both been using one of these puppies (usually for rigging anchors on gear, but they work fine on bolts too) for close to a year now.
No complaints. A lot of compliments in fact. We love it. Very quick and simple to rig, but also very versatile. Comes as close as you can to real SRENE. Isn't gear intensive. What's not to like?
Edit: Regarding security of the knots, I have no concerns. I'm quite confident that the failure mode would have to be breakage of the cord, and I just don't see the forces going that high.
I'm willing to trust knots-on-bights in my slings and ropes. I see no reason not to do so here.
(This post was edited by ja1484 on Apr 11, 2008, 3:50 AM)
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shockabuku
Apr 11, 2008, 4:17 AM
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Three strand equalette is one side going to two pieces and the other side to only one piece?
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moose_droppings
Apr 11, 2008, 4:23 AM
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shockabuku wrote: Three strand equalette is one side going to two pieces and the other side to only one piece?
Yes, and it equalizes on two pieces, one leg on each side.
(This post was edited by moose_droppings on Apr 11, 2008, 4:27 AM)
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shockabuku
Apr 11, 2008, 4:27 AM
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Right, it's a terminology issue. I haven't perused that thread for some time. Thanks.
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mattltambor
Apr 11, 2008, 5:31 AM
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Interesting thread. I was wondering if it might be better to re-thread the overhand on a bight with the third strand (like tying a water/tape knot) before tying the double fisherman's? Don't know if this would make much difference but I just thought of it while looking at asdf's pics.
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ja1484
Apr 11, 2008, 11:58 AM
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shockabuku wrote: Three strand equalette is one side going to two pieces and the other side to only one piece?
Actually, I believe in the context of this thread, we're talking about the "three strand powerpoint". It rigs up like a typical equalette, resulting in 2 legs off of 2-4 pieces, depending on circumstances.
Re-read the first page or so.
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karlbaba
Apr 12, 2008, 4:17 PM
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Basically though, in almost any decent rock, anchors should never be so sketchy that perfect equalization should be needed.
The lack of shock-loading afforded by a regular cordalette may be better protection that perfect equalization.
Also, the time savings afforded by any system that's significantly faster to employ might afford more safety than a slower, better equalized system. Time is safety on longer climbs.
Here's my idea, if you REALLY need the best anchor protection on some sketch rock, just clip a shorty screamer to each piece (or at least one or two of them) and rig a regular cordalette anchor to the screamers.
If the system gets stressed enough to be an issue, the screamers will extend, leading to perfect equalization with no shock load, and also absorb energy from the situation at the same time.
How's that sound Largo?
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ja1484
Apr 12, 2008, 4:50 PM
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karlbaba wrote: Basically though, in almost any decent rock, anchors should never be so sketchy that perfect equalization should be needed.
Agreed
In reply to: The lack of shock-loading afforded by a regular cordalette may be better protection that perfect equalization.
Shock loading doesn't exist if the climbing rope is in the system.
In reply to: Also, the time savings afforded by any system that's significantly faster to employ might afford more safety than a slower, better equalized system. Time is safety on longer climbs.
With a little practice, the equalette is just as fast to rig as a cordelette. On two piece anchors, it's generally faster. Just gotta get comfortable feathering clove hitches for the rest. Regardless we're talking about a matter of a minute or two. Unless it's a speed run, it's an immaterial difference.
This is why I made the switch - better equalization with no cons.
In reply to: Here's my idea, if you REALLY need the best anchor protection on some sketch rock, just clip a shorty screamer to each piece (or at least one or two of them) and rig a regular cordalette anchor to the screamers.
Should work fine, but it's more gear ya gotta carry.
(This post was edited by ja1484 on Apr 12, 2008, 4:58 PM)
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karlbaba
Apr 12, 2008, 5:03 PM
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It's my opinion that there will be shock-loading in any system that has some "extension" in it, if one of the pieces fails. Perfect equalization usually means allowing some extension.
If an anchor piece fails, the anchor is going to be shock-loaded
peace
Karl
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ja1484
Apr 12, 2008, 5:11 PM
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karlbaba wrote: It's my opinion that there will be shock-loading in any system that has some "extension" in it, if one of the pieces fails. Perfect equalization usually means allowing some extension. If an anchor piece fails, the anchor is going to be shock-loaded peace Karl
Per the research at Sterling ropes, best evidence available suggests that's just not the case so long as the dynamic rope is the attachment to the system. The numbers suggest no shockloading and, at times, lower forces than the initial impact.
Until someone can point me to *other* available evidence suggesting otherwise, I'm sticking with the best evidence we have at this time.
(This post was edited by ja1484 on Apr 12, 2008, 5:14 PM)
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